Association between the dopamine D2 receptor TaqI A2 allele and low activity COMT allele with obsessive-compulsive disorder in males.

BACKGROUND Mounting evidence suggests the involvement of the dopamine system in the pathophysiology of obsessive-compulsive disorder. METHOD The relationship of the dopamine D(2) receptor (DRD2) TaqI A, and catechol-O-methyl-transferase (COMT) NlaIII High/Low activity polymorphism to obsessive-compulsive disorder (OCD) was examined in a sample of 150 patients and 150 controls. RESULTS OCD patients did not show significant differences in genotype distribution and allele frequency for polymorphisms investigated relative to controls. However, when the sample was stratified by gender, there was a trend to a significant predominance of the DRD2 A2A2 genotype (p=0.049), and a higher frequency of the DRD2 A2 allele (p=0.020) and low-activity COMT allele (p=0.035) in male OCD patients compared to male controls. In addition, we observed an association of the DRD2 A2A2 genotype in patients with an early onset of disease (<or=15 years) (p=0.033). CONCLUSIONS Our findings replicate previous reports and provide support for a potential role of the COMT and DRD2 locus in subgroup of male, early onset patients with OCD.